Bluerock Diamonds Plc (LON:BRD) has raised £350,000 to fund development of a second kimberlite pipe at the Kareevlei diamond mine in South Africa.
Mining at the new pipe, K1, is ahead of schedule with some 107,000 tonnes of waste already dug out and first blasting expected in the next 3-4 weeks.
The new pipe is close to the existing K2 operation and the two will be mined at the same time.
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K1 has an inferred grade of 6.3 carats per hundred tonnes (cpht) or 40% higher than the inferred grade of K2.
Changes to the crushing circuit, meanwhile, have boosted throughput to an average 1,350 tonnes a day (equivalent to over 28,000 tonnes a month.
Final changes to the crushing plant will be completed in June, which is expected to boost volumes further.
Adam Waugh, chief executive, said: "We are pleased that the changes to our crushing circuit have achieved the desired result but we continue to seek ways of increasing production levels further.
“We are excited about beginning to mine K1 with the prospect of a significant increase in grade.”
The price of the shares in the placing was 1.2p.
BlueRock raised £500,000 in March when it started to develop K1.